Solid state image sensors are made of a grid of many smaller sensor elements. Each of these sensor elements is commonly referred to in the art as a “pixel.” In operation, light shone on the active pixels generates an electrical charge that is translated into a digital image. Since image sensors are used for color imaging, in many cases, a color filter array (CFA) is placed over the image sensor. However, in order to separate the light into color bands or components, color separation inputs are required. Depending on the configuration of the image sensor, some times these CFA are spaced apart from each other. When doing this spacing, it is desirable to use some type of light blocking or light absorbing material. This color separation is achieved in many ways in the prior art.
One such way is to have chromium oxide and chromium metal disposed on a substrate. Although satisfactory, this arrangement includes drawbacks. One such drawback is that light intended for one color channel may be reflected or directed to another color channel. For example, and referring to FIG. 1, a portion of the light (not shown) passes to its intended pixel 20. Another portion of the light is absorbed by the chromium oxide 15 as shown, and an undesirable stray portion of the light passes through a first color filter 10 at an angle such that it is not absorbed by its intended pixel 20, but instead passes to the substrate 23 of the color light sensing device 25 that is beneath the black light shield 35. This light is then reflected by the chromium metal surface of the black light shield 35 to an adjacent color channel 30. This is obviously undesirable.
Consequently, a need exists for a black light shield that prevents light from one color channel from being reflected or directed to another color channel.